We recently reported that you should probably wash your bath towel after every three to four uses – something that the majority of us fail to do.

The true extent of just how dirty unwashed towels can get is starting to come to light, with new research revealing that the vast majority of towels are contaminated with potentially disease-causing bacteria.

Dr. Charles Gerba, a microbiologist at the University of Arizona, is currently working on an as-yet unpublished study in which he found that nearly 90% of bathroom towels were contaminated with coliform bacteria (organisms that can indicate the presence of disease-causing bacteria in water), while roughly 14% carried E. Coli. In some instances, he has even found traces of salmonella. Speaking to Time, he said:

"After about two days, if you dry your face on a hand towel, you're probably getting more E. coli on your face than if you stuck your head in a toilet and flushed it."

Why so dirty?

Towels are the perfect bacteria trap because every time we use them we transfer natural skin bacteria onto their surface, along with any other germs we might be carrying. In addition to this, towels that remain damp for a while after use also have the potential to become a breeding ground for dangerous bacteria – such as the 'superbug' MRSA, which was identified on the towels of college football players in a 2003 study.

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However, while this might sound totally gross, it's not quite as dangerous as it seems. Our bodies are adapted to being able to live in an environment that has microbes all around, so using your own towel that is covered in your own bacteria is very unlikely to have any negative health effects. Indeed, even when it comes to somebody else's towel, the chances of getting sick stay relatively slim. Susan Whittier, director of clinical microbiology at New York-Presbyterian and Columbia University Medical Centre says it's highly unlikely that an individual will get sick from simply touching a used towel. She adds:

"As long as it's drying completely between use, there's almost no chance of passing bacteria from one person to another."

The real risk comes when someone using a towel has open cuts, abrasions or very dry skin, as this can let microbes into your system.

So, the bottom line? Although kitchen and bathroom towels will never be 100% germ-free, the best way to reduce any potential health risks is to stick to a regular washing routine and to keep towels as dry as possible between uses.